The over-all objective of this research is to study the functional properties of abnormal human hemoglobins by measuring their oxygen binding equilibria under various conditions of pH and salt concentrations, and in the presence and absence of certain organic phosphates. The results will be used in an attempt to explain the presence or lack of clinical abnormalities such as erythrocytosis or anemia associated with a specific abnormal hemoglobin and to extend our understanding of the contribution of specific amino acid residues in hemoglobin to its oxygen transport function. The studies will be divided into two levels of investigation. The first level will consist of screening all previously unstudied and all new mutant hemoglobins available to our laboratory for general parameters of oxygen binding (P50, Hill's "n" coefficient of cooperativity, Bohr effect, and influence of organic phosphate on P50). The second level of investigation will be to measure the oxygen-hemoglobin equilibrium curve as completely as possible for those mutants which have altered function. The results will be analyzed in terms of the Adair equation and other models for oxygenation of hemoglobin. Attempts will be made to identify which steps in the sequencial oxygenation of hemoglobin are most altered by the mutant change in structure. The principal method used in the research will be the measurement of oxygen equilibrium curves by an automatic recording system which measures fractional saturation of hemoglobin and oxygen pressure simultaneously over a range of less than 1% saturation to over 99% saturation.